When concrete structures such as walls and floors are formed, electrical and/or telecommunications boxes (referred to collectively below as “electrical boxes”) may be positioned in a form prior to pouring viscous concrete into the form. Once the form is in place, the boxes and associated conduits can be positioned in the form. Viscous concrete can then be poured into the form. After the concrete sets, the electrical boxes will be encased in the set concrete and can be used to house electrical or telecom wires in the concrete structure.
Currently, installers cover the opening of the electrical box with duct tape in order to prevent intrusion of poured concrete into the box. This is time consuming because every electrical box must be individually covered with duct tape. Also, if there is not a complete seal around the opening, concrete can enter into the electrical box making it difficult or impossible to pull wires through. Finally, once the concrete has been poured and set, the duct tape must be pulled or scraped off, piece by piece, and any concrete that got past the tape must be cleaned out. This process is described in U.S. Pat. No. 6,998,531, which references the use of duct tape and blown foam for preventing intrusion of poured concrete. The advantage of using blown foam is questionable, since it is still difficult and time consuming to remove the foam from the boxes. Also, blown foam may not produce an adequate seal against concrete intrusion. In view of the foregoing, there is a need for an improved system for preventing intrusion of poured concrete into electrical or telecom boxes.